In general, small gas turbines, such as micro gas turbines, are so structured that a generator, a compressor, and a turbine are disposed on one and the same rotating shaft rotor in this order as disclosed in Patent Document 2. Permanent-magnet generator rotors having a permanent magnet are used as generators for use in such a gas turbine. As a permanent-magnet generator rotor, a generator rotor formed by integrating a columnar permanent magnet and a bearing portion by shrink fitting using a non-magnetic metal pipe is disclosed in Patent Document 1. Patent Document 3 discloses that an end of a shrink-fit non-magnetic metal pipe (supporter) is fixed to an end of a permanent magnet rotor by welding.
Patent Documents 2 and 3 disclose that a permanent-magnet generator rotor, a compressor, and a turbine are coaxially disposed and integrated by fixing them by a tie-bolt and a nut. Patent Document 4 discloses the configuration of a permanent-magnet generator rotor.
Patent Document 1: U.S. Pat. No. 4,667,123
Patent Document 2: JP-A-2001-012256
Patent Document 3: JP-A-2004-232532
Patent Document 4: JP-A-2004-336917